I support the LED idea. I've seen some awesome WH40k figures with LEDs, and they tend to work very well for energy shields. I would say to take some inspiration for ZeroEdge's stuff on what you can do as far as customization goes.

Also, to save Ranalcus the time, he already said he was going to use eye decals.

You should prime it before using light colors.
I recommend using white primer, then test skin colors somewhere else before painting the Shinki. "Fleshtone" is that wierd color, just like fleshtone band-aids (no one has that skin color! so why make it?! O_o ) not really anime-esque light skin color, which I suppose is what you want, so you'll need to find a better color for that.

If you want to avoid sanding down again, you might be able to use some sort of paint stripper, depending on what type of paint you used. Be careful about that, though; some paint strippers can also warp or even dissolve certain types of plastic. Again, you should probably test on something you don't care about to make sure it works; perhaps the sprue used for holding the little bitz that come with Shinkis?

Rubbing alcohol and scrubbing with a magic eraser (http://en.wikipedia.org/wiki/Melamine_foam, they're a pretty common housekeeping item) is a safe/effective way to remove paint. Shinki bodies are made of polystyrene and the hands and feet are vinyl, so you'll need acrylic primer instead of enamel. The primers sold for plastic wargaming miniatures are durable and plastic-safe.